Add SkImage::MakeFromYUVATexturesCopyToExternal

Updated API for creating a RGBA texture-backed image from RGBA texture
planes with user-provided backing store using GrYUVABackendTextures.

Ultimately we would like to remove all such APIs and have the client
make a SkSurface and draw a YUVA texture image to the surface but
a recent attempt to do that in Chrome caused a not yet understood
perf regression.

Add wacky_yuv_formats variation that tests new api.

Bug: skia:10632
Change-Id: I89411216948682f13281a91a7575d5f345badda7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/329956
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
9 files changed